Rice is the most popular food in the world, providing sustenance to more than 3.5 billion people each day.

Rice is deeply embedded in food, daily rituals, language and spirituality. It is easy to take it for granted.

But where did rice come from? And how did it spread to become the foundation of global food security?

Early origins in China and India

In the lower reaches of the Yangtze River, China, Oryza sativa rice grew 100,000 years ago. It was first gathered by humans 24,000 years ago, and cultivated 13,000 years ago.

Changes to the plant through selective breeding resulted in a domesticated plant distinct from the wild varietal about 11,000 years ago.

There is debate about how early forms of domesticated rice developed outside of China, but there is evidence of parallel rice cultivation in India along the Ganges in Uttar Pradesh as early as 6500 BCE.

One possibility is that the two most common subspecies of rice, short-grained (japonica) and long-grained (indica) developed separately: the former in China and the latter in India.

A related theory is that indica is a hybrid between a local Indian rice and japonica, introduced to India around 2500 BCE.

African rice: the other origin story

Another rice species, Oryza glaberrima, developed in Africa some 2,000 years after rice was........

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